Mid-handle drill construction and assembly process

ABSTRACT

A power tool can include a gear case, a motor having first and second sets of lead wires, a housing assembly, and a field case. The field case may include a front portion configured for engaging the gear case and a rear portion. The housing assembly may include first and second generally symmetrical housing segments configured for engaging the field case and forming a mid-handle grip. The first set of lead wires may be routed through the front portion of the field case directly to a trigger switch assembly. A method for assembling a mid-handle power tool is also provided and may include routing lead wires through a ventilation path between the field case and trigger assembly.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 11/986,668 filed on Nov. 21, 2007. This disclosure of the aboveapplication is incorporated herein by reference

The present disclosure relates generally to power tools such as drills,screwdrivers, and hammer mechanisms, and more particularly to a powertool having a mid-handle grip housing and an assembly process for thesame.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

A common problem with power tools, particularly portable power tools ofthe mid-handle configuration having a “jam-pot” construction, concernsthe ability with which a power tool so constructed may be assembled.Typically, power tools having a jam-pot construction may be assembled ina process wherein the subcomponents which form the wiring are initiallyinstalled into a first jam-pot opening and thereafter, the subcomponentsmay be fed out through a second jam-pot opening.

An often and time-consuming operation in this process concerns theconnection of the wires from a power source such as a cord or a batterypack to the trigger switch and motor assembly. In a mid-handle tool, theconnection of these wires can require that the tool be reorientedmultiple times. The assembly operation may be such that the wires arerouted through narrow openings in the housing to later be connected tothe field and brushes. The tool may need to be reoriented to make theseconnections. Additionally, lead wires may be prone to being trapped orpinched between the housing components during the assembly process.

In addition, portable power tools of the mid-handle configuration havinga “jam-pot” construction are generally complex to mold. For example, thejam-pot is typically molded with at least a portion of the handleattached thereto. This typically requires the use of multiple additionalcomponents such as a housing end cap and a separate handle housingportion.

SUMMARY

A power tool is provided including a gear case, a motor having at leastone set of lead wires, a housing assembly, and a field case. The fieldcase may include a front portion configured for engaging the gear caseand a rear portion. The housing assembly may include first and secondgenerally symmetrical housing segments configured for engaging the fieldcase and forming a mid-handle grip. At least one set of lead wires maybe routed through the front portion of the field case to a triggerswitch assembly.

In another aspect, the present teachings provides a power tool housingassembly comprising a base housing segment and a cover housing segmentgenerally symmetrical to the base housing segment. Each housing segmentmay include a plurality of assembly bosses defining a respectiveplurality of apertures accessible from an exterior of the housingassembly. A field case may be provided having at least one fasteningboss defining an aperture accessible from an interior of the housingassembly and configured for attaching the field case to an interior ofthe base housing segment. The field case, base housing segment, andcover housing segment cooperate to form a housing assembly. In variousembodiments, the housing assembly may include an end cap and amid-handle grip integrally connected via a bridge section having alongitudinal parting line.

In yet another aspect, the present teachings provide a power toolcomprising a motor, a field case, a self contained gear case assembly,and a housing assembly. The field case has a front portion for engagingthe gear case assembly and a rear portion. The field case may define agenerally cylindrical chamber for receiving the motor. The gear caseassembly may include a metal gear case and a cover plate, wherein thecover plate is secured to the gear case and is not removably accessiblefrom an exterior of the power tool. The housing assembly may bepartially defined by the field case and include first and secondgenerally symmetrical housing segments forming a mid-handle grip andconfigured for engaging the field case and gear case.

The present teachings further provide a method of assembling amid-handle power tool. The method includes providing a housing assemblyhaving first and second generally symmetrical housing segments. Invarious embodiments, the housing assembly forms an end cap and amid-handle grip connected by a bridge section. At least one set of leadwires may be connected to a motor. The wires can be routed to the frontportion of a field case while the motor is pressed into the field casefrom the front portion. The field case defines a generally cylindricalchamber for receiving the motor and is attached to a gear case and thefirst housing segment. The second housing segment can be attached to thefield case and the first housing segment.

According to one example, a combined gear case housing assembly iscreated by coupling a gear case cover to a gear case housing cooperatingattachment features located inside an outer radial periphery of the gearcase housing. A field case assembly is coupled to the combined gear casehousing assembly using cooperating attachment features located outsidean outer radial periphery of the gear case housing. A pair of clamshellhousing elements is coupled to the field case assembly to each otherforming a mid-handle grip. Each of the gear case housing, the field caseassembly, and the pair of clamshell elements forms a part of a finalexterior housing the mid-handle power tool.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is side perspective view of an assembled exemplary power toolconstructed in accordance with the teachings of the present;

FIG. 2 is a partial perspective view of the power tool as illustrated inFIG. 1;

FIGS. 3 a and 3 b is are exploded views of the power tool as illustratedin FIG. 2;

FIG. 4 is a side plan view of the power tool of FIG. 1 with the coverhousing segment removed;

FIG. 5 is a perspective view of a field case according to the presentdisclosure;

FIG. 6 is an alternate perspective view of a field case according to thepresent disclosure; and

FIGS. 7A and 7B are partial magnified views of FIG. 6; and

FIG. 8 is a partial perspective view of a gear case according to thepresent disclosure.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

With reference to FIGS. 1 through 8 of the drawings, a power toolconstructed in accordance with the present teachings is generallyindicated by reference numeral 10. As those skilled in the art willappreciate, various embodiments of the power tool of the presentdisclosure may be either a corded or cordless (battery operated) device,such as a portable screwdriver, drill, impact wrench-type power tool,hammer drill, and other mid-handle type power tools.

In the particular embodiments illustrated herein, the power tool 10 is acorded drill having a two component clam shell housing assembly 12having a longitudinal part line 23. The power tool 10 is provided with amotor assembly 14, a field case 16 configured to house the motorassembly 14, a gear case 18 having a gear assembly, a trigger switchassembly 20, and a power cord (not shown).

Those skilled in the art will understand that several of the componentsof power tool 10, such as the motor assembly 14, gear assembly, chuck,and trigger details, may be conventional in nature and need not bedescribed in significant detail in this application. Reference may bemade to a variety of publications for a more complete understanding ofthe operation of the conventional features of power tool 10. One exampleof such publications is commonly assigned U.S. Pat. No. 5,897,454 issuedApr. 27, 1999, the disclosure of which is hereby incorporated byreference as if fully set forth herein.

The power tool housing assembly 12 of the present disclosure can beformed from first and second housing segments 22, 24, such as claimshell-type halves, and a plurality of fasteners, such as screws. Each ofthe first and second segments 22, 24 can be generally symmetrical andinclude cooperating halves of an end cap 26 and a mid-handle grip 28separated by an integral bridge section 30 extending there between. Thefirst and second segments 22, 24 are joined together along alongitudinal parting line 23. In various embodiments, the field case 16can form at least a portion of the exterior surface of the power tool10. The housing segments 22, 24 can be formed from injection moldedplastic or a similarly suitable material and may be referred toindividually herein as a base housing segment 22 and a cover housingsegment 24. It should be understood that while the present disclosuremay refer to certain features, elements, or parts in a dimensionalrespect, such reference is not meant to be limiting, and it isenvisioned that elements such as the base housing segment and coverhousing segment may, in certain instances, be interchangeable with oneanother.

The fastening devices, or screws, that typically secure clam shell-typehousing halves together can go through both housing segments, and insome cases can go additionally through a boss on the field case.According to the present disclosure, each housing segment 22, 24 canhave an interior surface 22 a, 24 a and exterior surface 22 b, 24 b andmay include a plurality of assembly screw bosses 32 laterally disposedthroughout the end cap 26 region, the mid-handle grip 28, and the bridgesection 30. Each assembly boss 32 can have an aperture 34 for receivinga suitable threaded fastener configured to secure the power tool housingassembly 12 together. The apertures 34 can be accessible from theexterior of either of the housing segments 22, 24.

At least one of the housing segments, such as the base housing segment22, can include at least one intermediate fastening boss 36. Theintermediate fastening boss 36 may define an aperture 38 accessible froman interior of the base housing segment 22 and is configured forattaching the field case 16 to an interior surface 22 a of the basehousing segment 22. In certain embodiments, the intermediate fasteningboss 36 may not be accessible from an exterior of the power tool 10. Asdescribed in more detail below, by using the intermediate fastening boss36 and separately fastening the field case 16 to the base housingsegment 22 first, various wire leads may be routed within the housingassembly 12 and secured to certain areas such that when the coverhousing segment 24 is attached to the base housing segment 22. In thisrespect, there is less opportunity for such wire leads to be pinched orcompromised between various portions of the housing assembly 12.

In one example, the motor assembly 14 can include a motor that iscoupled to a typical output spindle and chuck by way of a gear assembly(details not shown). The gear assembly can be housed in a typical gearcase assembly 18 and may simply be a shaft or transmission providingdrive from the motor assembly 14 through a gear train. In certainembodiments, the power tool includes a self-contained gear case assemblythat may include a gear case and a cover plate 80 secured thereto withinternal fasteners 82 as best shown in FIG. 8. With such a design, thecover plate 80 is not removably accessible from an exterior of the powertool 10. For example, the gear case 18 would need to be detached fromthe field case 16 prior to removing the cover plate 80 since the coverplate fasteners would otherwise be concealed.

The gear case 18 includes a housing 76 that defines an outer surface 78.It is understood that the outer surface 78 of the gear case housing 76partially defines the overall outer surface of the power tool 10. Inother words, the outer surface 78 is exposed to allow a user to hold andgrip the outer surface 78 during use of the power tool 10.

The cover plate 80 is coupled to the gear case housing 76 via aplurality of first fasteners 82. As shown in FIG. 8, the first fasteners82 are arranged in a first pattern 84 (represented by a bolt circle inFIG. 8). The first fasteners 82 can be located within the periphery ofthe gear case housing 76 and can hold the cover plate 80 against a lip(not shown) within the gear case housing 76. In one embodiment, the gearcase 18 includes a seal (not shown) between the gear case housing 76 andthe cover plate 80, which reduces leakage of any lubricant (not shown)out of the gear case 18.

The gear case 18 and the field case are coupled via a plurality ofsecond fasteners 88 (FIG. 1). In the embodiment represented in FIG. 8,the second fasteners 88 are arranged in a second pattern 90 (representedby a bolt circle in FIG. 8). As shown, the second pattern 90 of thesecond fasteners 88 has a larger periphery than the first pattern 84 ofthe first fasteners 82. In other words, the second fasteners 88 arefurther outboard than the first fasteners 82. Thus, when the gear case18 and the field case 16 are coupled, they cooperate to enclose thefirst fasteners 82.

Also, in the embodiment shown, the cover plate 80 can include aplurality of pockets 92. The pockets 92 can be provided such that theheads of the first fasteners 82 are disposed beneath an outer surface 94of the cover plate 80. As such, the first fasteners 82 are unlikely tointerfere with the coupling of the gear case 18 and field case 16.

The cover plate 80 may also include a plurality of projections 96 thatextend from the outer surface 94. The projections 96 extend into thefield case 16 to ensure proper orientation of the gear case 18. Thecover plate 80 may further include a first aperture 98 for an outputmember (not shown) of the motor assembly 14 that may extend therethrough.

In various embodiments, the motor assembly 14 can be housed in a fieldcase 16. A typical power cord can supply current from an AC source tothe motor assembly 14 and can be controlled by the trigger switchassembly 20. The motor assembly 14 may include a first set of lead wires40 routed from the motor field to the trigger switch assembly 20 and asecond set of wire leads 42 routed from the commutator brushes (notshown) to the trigger switch assembly 20.

The field case 16 may be made of a non-metallic material, such asinjection molded plastic, and may define a generally cylindricalinterior chamber 44 for receiving the motor 14. The field case 16 mayhave a front portion 46 for engaging the gear case 18 and a rear portion48, at least a portion of which may be covered by the end cap 26. Thefront portion 46 may include one or more laterally extending bosses 50configured for securing the field case 16 to the gear case 18 viafastening devices. The fastening devices can be screws extending throughthe apertures of bosses 50 and mating with cooperating threads providedin a metal gear case 18. In various embodiments, the field case 16 mayform a part of the exterior housing of the power tool 10.

As best shown in FIG. 5, the field case 16 may define one or moreventing apertures 52 formed within the front portion 46. In theassembled power tool 10, the apertures 52 partially define a ventingpath to provide fluid communication between the exterior of the housingassembly 12 and the interior of the power tool 10, including an interiorarea of the mid-handle grip 28. The venting path is configured to allowthe passage of intake or exhaust air flow there through. In variousembodiments, the housing assembly 12 may further be provided with one ormore apertures, or slots, to additionally allow for air to either betaken in or exhausted, depending on the location of the slots andplacement of an armature fan unit, through the mid-handle 28 via vents29 therein. In this way cooling airflow can be provided over the switch20 located in the midhandle 28. Additional venting apertures, or slots,can be located in the parts of the clam shell halves 22, 24 that formthe end cap 26.

As shown in FIGS. 2 and 5, the field case 16 may be provided with asuitable recessed area 53 configured to house an armature fan unit 54.The fan unit 54 can include a fan member 54 a and a baffle 54 b and mayserve to vent the motor 14, the gear case 18, or both. Additionally, thefan unit 54 may be used to aid in cooling of the trigger switch assembly20 and its electronics that may be located within an interior 56 of themid-handle grip 28. For example, such an intake or exhaust configurationmay create an air flow that can be directed via vents 29 to pass throughthe interior 56 of the mid-handle grip 28 and over the internal portionof the trigger switch assembly 20, which may often be a heat sink. Thiswould allow the trigger switch assembly 20 to be adequately cooled ormaintained at a suitable operating temperature.

In various embodiments, the present disclosure provides a simplifiedmethod for wiring a trigger switch assembly 20 in a mid-handle powertool 10. Once a first set of lead wires 40, or field wires, is connectedto the motor 14, the field wires 40 can be folded or routed to a frontportion 46 of the field case 16 while the motor 14 is being press fittedtherein. In this manner, the wires would not have to be fished out fromthe back of the assembly. The field wires 40 may be routed out of afront end of the field case 16 and through the lowermost ventingaperture 52, and past the fan unit 54 area. In certain embodiments asbest shown in FIG. 5, the field case 16 may comprise one or moreretaining slots 58 adjacent a venting aperture 52. In particular, oncepast the fan recessed area 52, the field wires 40 exit out the bottom ofthe field case 16 through the retaining slots 58 and connect to thetrigger switch assembly 20. In certain embodiments, the fan 54, and inparticular the fan baffle 54B, can be juxtaposed to the retaining slots58 and positioned to secure the field wires 40 within the retainingslots 58. This type of wire routing enables the use of shorter wires,leading to cost savings and ease of manufacturing.

As one skilled in the art can appreciate, routing the field wires 40through a ventilation path may allow for a more compact power toolhousing design, for example, by minimizing additional separate spacenecessary in the housing assembly used for wiring purposes. This designis also less prone for pinching or compromising a wire during theassembly process. In certain aspects, the field wires may be attached tothe trigger switch assembly 20 prior to pressing the motor 14 into thefield case 16.

The present disclosure also provides a method of securing lead wireswithin the housing assembly 12. As shown in FIGS. 4-8, a second set oflead wires 42, or brush leads, may be attached to the motor and arerouted through a rear portion 48 of the field case 16 to commutatorbrushes (not shown). Such lead wires 42 may be attached prior toassembly of the motor 14 into the field case 16 or after the insertionof the motor 14. The brush leads 42 may continue through the bridgesection 30 of the housing assembly 12 and are routed to the triggerswitch assembly 20. In certain aspects, as best shown in FIGS. 7A and7B, the field case may include one or more wire retention members 62configured for securing the brush wires 42 in the bridge section 30. Forexample, the wire retention members 62 may extend from, and beintegrally formed with, a lower region of the field case 16. As shown inFIG. 4, in various embodiments, this second set of lead wires is routedduring an intermediate assembly stage, in particular, after the basehousing segment 22 is attached to the field case 16 and prior to thecover housing segment 24 being attached.

In other embodiments, the bridge section 30 of at least one of the basehousing segment 22 and the cover housing segment 24 may be provided withsimilar wire retention members 62. It is envisioned that if two or morewire retention members are used, they may be orientated in alternatingdirections so as to better retain the brush wires 42. The bridge section30 of at least one of the base housing segment 22 and the cover housingsegment 24 may be provided with wire retention members 62 in the form ofextending webs or rib sections (not shown) that provide structuralsupport to the bridge section 30 and may improve the integrity of thehousing assembly 12 when high torque is applied to the power tool 10.Alternatively, such extending webs or rib sections (not shown) may beprovided independent of the wire retention members 62.

In various embodiments of the present disclosure, the field case 16 mayinclude at least one assembly boss 64 defining an aperture 66 configuredfor cooperating with the base housing segment 22 intermediate fasteningboss 36 for attaching the field case 16 to an interior 22 a of the basehousing segment 22. A fastening member can be used to engage each of thebase housing segment 22, cover housing segment 24, and field case 16 tosecure the housing assembly 12. The field case 16 may be mounted to thebase housing segment 22 as a separate step. Once secure, other parts maybe attached in place, such as the trigger switch assembly 20, and thelead wires 40, 42 can be routed accordingly. The lead wires 40, 42 canbe held in place through the bridge section 30 by the wire retentionmembers 62. This can help prevent or eliminate the possibility ofgetting wires pinched between the housing segments 22, 24 and the fieldcase 16.

As one skilled in the art can appreciate, a strong connection betweenthe field case 16 and gear case 18 may minimize potential damage to thepower tool 10 in the event of a sudden drop or other impact. Since thegear case 18 is typically aluminum or other metal, in certainembodiments the fastening devices, such as screws, are tapped into thegear case bosses 70 as opposed to the field case bosses 50, so that theymay be held by stronger metallic threads. This may also increase thetorque holding capability and the creep resistance of aluminum threadsmay result in a more consistent joining of the parts.

In various embodiments, a rear portion of the gear case 18 may includeone or more protruding or longitudinally extending attachment member 72,such as a screw boss, that will cooperate with a fastening device toattach the gear case 18 to at least one of the first and second housingsegments 22, 24. In this instance, at least one of the first and secondhousing segments 22, 24 may be provided with a cooperating attachmentmember 74 as shown in FIG. 4. As shown, the cooperating attachmentmember is disposed a sufficient distance away from the mid-handle gripin order to couple the housing assembly 12 to the gear case 18. As shownin FIG. 4, the attachment member is located at a distal end, in front ofthe mid-handle grip. Further mounting examples are also shown commonlyassigned U.S. Pat. No. 6,446,734 issued Sep. 10, 2002, the disclosure ofwhich is hereby incorporated by reference as if fully set forth herein.

According to one method of assembly, a combined gear case housingassembly 18 is created by coupling a gear case cover 80 to a gear casehousing 76 using cooperating attachment features located inside an outerradial periphery of the gear case housing 76, as best illustrated inFIG. 8. In one example, this may include locating fasteners 82, such asscrews, into cooperating threads located in an interior of the gear casehousing 18 (as shown by a bolt circle 84 in FIG. 8). A field caseassembly 16 may then be coupled to the combined gear case housingassembly 18 using cooperating attachment features, such as fasteners 88and cooperating threads, located outside an outer radial periphery ofthe gear case housing 76 (as shown by a bolt circle 90 in FIG. 8).

The pair of clamshell housing elements 22, 24 is then coupled to thefield case assembly 16 and then to each other, forming an integralmid-handle grip 28 and end cap 26. As shown in FIG. 1, each of the gearcase housing 76, the field case assembly 16, and the pair of clamshellelements 22, 24 forms a part of a final exterior housing of themid-handle power tool 10.

In certain embodiments, one of the pair of clamshell housing elements(the base housing segment 22) is coupled to the field case assembly 16as an intermediate step. Thereafter, the other one of the pair ofclamshell housing elements (the cover housing segment 24) is coupled tothe field case assembly 16 and the base housing segment 22. According tothe present disclosure, at least one set of lead wires 42 is retainedadjacent to the field case 16 in the one of the pair of clamshellhousing elements, in particular, the base housing segment 22, prior tocoupling the other one of the pair of clamshell elements, or the coverhousing segment 24. Each of the pair of clamshell housing elements 22,24 may then be coupled to the gear case housing 76. In variousembodiments, the steps of coupling each of the pair of clamshell housingelements 22, 24 to the gear case housing 76 and the step of coupling thecoupling the pair of clamshell housing elements 22, 24 to each otheroccurs simultaneously.

Those skilled in the art will understand that in the normal operationand process of using such a power tool 10 according to the presentdisclosure, there is a risk of contact and damage that can accidentallybe made with existing electrical conduit and the wires inside, orplumbing pipes. Midhandle power tools, in particular, generally havetheir handle disposed close to the metallic gear cases. In certaininstances, a barrier may be provided to prevent or minimize a user'sfingers from contacting the gear case when a user's hands are in thenormal operating position. However, if the integrity of such a barrierwere to be compromised, the user may accidentally be subject to liveelectrical current if the power tool were to unexpectedly contact anelectrical source. To reduce these risks, in various embodiments, thepresent disclosure provides a mid-handle power tool that is grounded.For example, a ground path may be provided such that a risk of the gearcase becoming live if a drill bit touches a live wire is minimized. Inone embodiment, as best shown in FIG. 5, the gear case 18 may include aground lead extending there from for connection to a ground screw 73(i.e., via a separate ground wire) that may be fastened to a bossdisposed in one of the pair of clamshell housing elements 22, 24,wherein the ground screw 73 is, in turn, grounded to a power supply. Inanother embodiment, a connector may be provided (not shown) that has aground terminal for a more direct electrical connection between themotor and a ground line. In these instances, the motor power device canbe grounded when using a common corded power supply.

With the power tool housing design and assembly method of the presentdisclosure, the front routing of the field wires 40 and the securing ofthe brush wires 42 in the bridge section 30 simplifies the wire-up ofthe power tool 10. The assembly is simplified primarily because thefield wires 40 are routed a shorter distance, and the brush wires 42 areable to be secured in place, minimizing assembly concerns that the wiresmay be pinched or compromised. In addition, the routing of the wiresthrough ventilation paths eliminates the need for extra space within thehousing. The specific clam shell-type housing including a base housingsegment 22 and a cover housing segment 24 provides additional rigidityand integrity of the power tool 10.

While the invention has been described in the specification andillustrated in the drawings with reference to various embodiments, itwill be understood by those skilled in the art that various changes maybe made and equivalents may be substituted for elements thereof withoutdeparting from the scope of the invention as defined in the claims.Furthermore, the mixing and matching of features, elements and/orfunctions between various embodiments is expressly contemplated hereinso that one of ordinary skill in the art would appreciate from thisdisclosure that features, elements and/or functions of one embodimentmay be incorporated into another embodiment as appropriate, unlessotherwise limited above. Moreover, many modifications may be made toadapt a particular situation or material to the teachings of theinvention without departing from the essential scope thereof. Therefore,it is intended that the invention not be limited to the particularembodiment illustrated by the drawings and described in thespecification as the best mode presently contemplated for carrying outthis invention, but that the invention will include any embodimentsfalling within the foregoing description and the appended claims.

1. A power tool housing assembly comprising: a base housing segment anda cover housing segment generally symmetrical to the base housingsegment, each housing segment comprising a plurality of assembly bossesdefining a respective plurality of apertures accessible from an exteriorof the housing assembly, the base housing segment further comprising atleast one intermediate fastening boss defining an aperture accessiblefrom an interior of the housing assembly; and a field case having atleast one cooperating assembly fastening boss configured for attachingthe field case to an interior of the base housing segment, wherein thefield case, base housing segment, and cover housing segment cooperate toform a housing assembly that includes an end cap and a mid-handle gripintegrally connected via a bridge section and having a longitudinalparting line.
 2. A power tool housing assembly according to claim 1,further wherein the field case comprises at least one wire retentionmember configured to secure at least one lead wire within the bridgesection.
 3. A power tool housing assembly according to claim 1, whereinthe field case defines an aperture forming a ventilation path thatprovides fluid communication between the field case and an interior ofthe mid-handle grip.
 4. A power tool housing assembly according to claim1, wherein the field case further comprises at least one assembly bossdefining an aperture configured to align with one of the base and coverhousing segment assembly boss apertures such that a threaded fasteningdevice can engage each of the base housing segment, cover housingsegment, and field case.
 5. A power tool housing assembly according toclaim 1, wherein at least a portion of the field case defines anexterior surface of the housing assembly.
 6. A power tool housingassembly according to claim 1, wherein at least one of the base housingsegment and the cover housing segment further comprises an attachmentmember located a distance past the mid-handle grip and configured toattach with a gear case.
 7. A power tool housing assembly comprising: amotor field case; first and second clamshell segments coupled to themotor field case, the first and second clamshell segments being shapedgenerally symmetrical to each other and joined to each other along apart line extending longitudinally along the tool, the first and secondclamshell segments forming a mid-handle grip for the power tool and anend cap for the motor field case that are connected via a bridgesection; wherein the motor field case, the first and second clamshellsegments each form an exposed part of an overall tool housing.
 8. Apower tool housing assembly according to claim 7, wherein the motorfield case defines an aperture forming a ventilation path that providesfluid communication between the field case and an interior of themid-handle grip and wherein the mid-handle grip comprises a vent toprovide fluid communication between the interior of the mid-handle gripand the exterior of the tool.
 9. A power tool housing assembly accordingto claim 7, further comprising a metal gear case forming an exposed partof the overall tool housing located adjacent the mid-handle and anattachment member configured for securing a ground screw operable toground a metal gear case.
 10. A power tool housing assembly according toclaim 7, further comprising at least one wire retention memberconfigured to secure at least one lead wire within the bridge section.11. A method of assembling a mid-handle power tool, comprising: couplinga gear case cover to a gear case housing cooperating attachment featureslocated inside an outer radial periphery of the gear case housing,thereby creating a combined gear case housing assembly; coupling a fieldcase assembly to the combined gear case housing assembly usingcooperating attachment features located outside an outer radialperiphery of the gear case housing; coupling each of a pair of clamshellhousing elements, which together comprise a mid-handle grip, to thefield case assembly; and coupling the pair of clamshell housing elementsto each other; wherein each of the gear case housing, the field caseassembly, and the pair of clamshell elements forms a part of a finalexterior housing the mid-handle power tool.
 12. A method according toclaim 11, wherein coupling each of the pair of clamshell housingelements to the field case assembly comprises coupling one of the pairof clamshell housing elements to the field case assembly and thereaftercoupling the other one of the pair of clamshell housing elements to thefield case assembly.
 13. A method according to claim 12, furthercomprising retaining wires in the one of the pair of clamshell housingelements prior to coupling the other one of the pair of clamshellelements.
 14. A method according to claim 11, further comprisingcoupling each of the pair of clamshell housing elements to the gear casehousing.
 15. A method according to claim 14, wherein the step ofcoupling each of the pair of clamshell housing elements to the gear casehousing and the step of coupling the coupling the pair of clamshellhousing elements to each other occurs simultaneously.
 16. A methodaccording to claim 11, wherein the step of coupling each of a pair ofclamshell housing elements to the field case assembly comprisesproviding an end cap for the field case assembly.
 17. A method accordingto claim 11, wherein the step of coupling a gear case cover to a gearcase housing comprises screwing screws into cooperating threads locatedin an interior of the gear case housing, the screws and cooperatingthreads being the cooperating attachment features.
 18. A methodaccording to claim 17, wherein screwing screws into cooperating threadscomprises locating a head of each of the screws below an outer surfaceof the gear case cover.
 19. A method according to claim 17, wherein thestep of coupling the field case assembly to the combined gear casehousing assembly comprises screwing screws into cooperating threadslocated in protruding bosses of the gear case housing, the screws andcooperating threads being the cooperating attachment features.